Q2 / 150 · MHT CET 2026 (18 April Shift 2) · Chemistry
What is the oxidation state of chlorine in its weakest oxoacid?
- Correct answerA$+1$
- B$-1$
- C$+3$
- D$-3$
Solution
The oxoacids of chlorine are $HClO$, $HClO_2$, $HClO_3$, and $HClO_4$.
The acidic strength of oxoacids of a halogen increases with an increase in the oxidation number of the halogen atom. As the number of oxygen atoms increases, the electron density is pulled away from the $O-H$ bond, making it easier to release an $H^+$ ion.
The order of acidic strength is $HClO < HClO_2 < HClO_3 < HClO_4$.
Therefore, the weakest oxoacid of chlorine is hypochlorous acid, $HClO$.
Let the oxidation state of chlorine in $HClO$ be $x$.
The typical oxidation state of hydrogen is $+1$ and that of oxygen is $-2$. Since the molecule is neutral, the sum of oxidation states is zero.
$(+1) + x + (-2) = 0$
$x - 1 = 0$
$x = +1$
The acidic strength of oxoacids of a halogen increases with an increase in the oxidation number of the halogen atom. As the number of oxygen atoms increases, the electron density is pulled away from the $O-H$ bond, making it easier to release an $H^+$ ion.
The order of acidic strength is $HClO < HClO_2 < HClO_3 < HClO_4$.
Therefore, the weakest oxoacid of chlorine is hypochlorous acid, $HClO$.
Let the oxidation state of chlorine in $HClO$ be $x$.
The typical oxidation state of hydrogen is $+1$ and that of oxygen is $-2$. Since the molecule is neutral, the sum of oxidation states is zero.
$(+1) + x + (-2) = 0$
$x - 1 = 0$
$x = +1$
Hence, the correct answer is option: 'A'.